SLF4J

SLF4J-simple can't be configured via log4j.properties. To configure it use slf4j-log4j12

org.slf4j
slf4j-log4j12
1.5.8


WINDOW resize handler

public class XXX implements ResizeHandler{
public XXX(){
Window.addResizeHandler(this);
}

@Override
public void onResize(ResizeEvent event) {
//TODO YOUR CODE AFTER RESIZING
}

}

Date Formatter

Is the ParseException happens?

SimpleDateFormat df = new SimpleDateFormat("dd-MM-yyyy");
Date date = null;
try {
//1
date = df.parse("12-34-2007");
} catch (ParseException e) {
System.out.println("Wrong date");
}
System.out.println(date.toString());

Actually not. To prevent this add to //1
df.setLenient(false);

Letient parameter is true by default that's why to match format strictly need
setting parameter to false

Windows fonts

sudo apt-get install msttcorefonts

Converting image

As our Designer was fired because of crisis - I had to change images size. So imagemagic is excelent for this use.

mogrify -gravity Center -crop 30X22+0+0 *.png
mogrify -format png *.jpg
mogrify -resize 30x22+0+0 *.*
mogrify -resize 120% *.*

identify -format "%wx%h \n" *.*


Hibernate Custom Type

Database has for example wrong state and can't save 1 or 0, 'Y' or 'N', 'YES' or 'NO'
So you need to save state as 1 and 2. Seems that database need refactoring... yes you are right but if you can't? Here is decision - custom type

package com.types;

import java.io.Serializable;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;

import org.hibernate.HibernateException;
import org.hibernate.usertype.UserType;

public class OneTwoBooleanType implements UserType{

private final static int DB_TRUE = 1;
private final static int DB_FALSE = 2;

public Object assemble(Serializable cached, Object owner) throws HibernateException {
return cached;
}

public Object deepCopy(Object value) throws HibernateException {
return value;
}

public Serializable disassemble(Object value) throws HibernateException {
return (Serializable) value;
}

public boolean equals(Object x, Object y) throws HibernateException {
if(x==null){
return false;
}
return ((Boolean)x).equals(y);
}

public int hashCode(Object x) throws HibernateException {
return x.hashCode();
}

public boolean isMutable() {
return false;
}

public Object nullSafeGet(ResultSet rs, String[] names, Object owner) throws HibernateException, SQLException {
Number val = (Number) rs.getObject(names[0]);
if(val==null){
return false;
}
return val.intValue() == DB_TRUE ? true : false;
}

public void nullSafeSet(PreparedStatement st, Object value, int index) throws HibernateException, SQLException {
int dbValue;
if(value==null){
dbValue = DB_FALSE;
} else {
dbValue = (Boolean) value ? DB_TRUE : DB_FALSE;
}
st.setInt(index, dbValue);
}

public Object replace(Object original, Object target, Object owner) throws HibernateException {
return original;
}

public Class returnedClass() {
return Boolean.class;
}

public int[] sqlTypes() {
return new int[]{Types.SMALLINT};
}

}

And It's usage

@Column(name="INTERNAL_STATUS_ID")
@Type(type="com.types.OneTwoBooleanType")
private boolean isVisible;


Substract queries

If you need to check differences between tables use this query:

select * from t1
minus
select * from t2


Java version number


import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;

public class ClassVersionChecker {
public static void main(String[] args) throws IOException {
for (int i = 0; i < args.length; i++)
checkClassVersion(args[i]);
}

private static void checkClassVersion(String filename) throws IOException {
DataInputStream in = new DataInputStream(new FileInputStream(filename));

int magic = in.readInt();
if (magic != 0xcafebabe) {
System.out.println(filename + " is not a valid class!");
}
int minor = in.readUnsignedShort();
int major = in.readUnsignedShort();
System.out.println(filename + ": " + major + " . " + minor);
in.close();
}
}


1.Compile

javac ClassVersionChecker.java

2.Execute in unix console

find . -name *.class|xargs java -cp /c/tmp ClassVersionChecker|grep 50

where last number is class version

major minor Java platform version
45 3 1.0
45 3 1.1
46 0 1.2
47 0 1.3
48 0 1.4
49 0 1.5
50 0 1.6


Statistical SQL query

For example you need to count how many companies in which source system:

select count(*), source_system_id from company group by rollup(source_system_id)


Migration from JSF to GWT 1.5

As far as I had to fix small project I had a task to fix JSF application. I need:
1.Add sorting
2.Fix flow
What I have is ant with many libs and JSF version 1.1.2
Problems:
1.JSF doesn't support table sorting.So do use this I need to use extensions such as Tomahawk or Trinidad as far as I worked with Tomahawk I used it.Last version in maven repositary is Tomahawk 1.1.5 so I used it. JSF 1.1.2 is not compatible with it so I replaced it with myfaces 1.1.5.After that many operations in applications didn't worked I had a lot of time to fix

In the same time I started to write the same application but on GWT. The 1 problem was that JSF Bean has UI, SQL, POJO in 1 Bean.

Time estimations will be discuss later

Hibernate Filters

Task:
Show feed executors with specified date

Libraries:


org.hibernate
hibernate-annotations
3.3.1.GA


org.hibernate
hibernate-commons-annotations
3.3.0.ga



So Feed Entity:

@Entity(name="FEED")
@FilterDef(name="status", parameters=@ParamDef( name="date", type="date" ) )
public class Feed {

@Id
@Column(name="FEED_ID")
private int id;

@Column(name="NAME")
private String name;

@OneToMany(fetch=FetchType.EAGER)
@JoinColumn(name = "FEED_ID")
@BatchSize(size=50)
@Fetch(FetchMode.SELECT)
@Filter(name="status", condition="BUSINESS_DATE=(select max(x.business_date) from FEED_RUN x where x.BUSINESS_DATE <= :date AND FEED_ID=x.FEED_ID)")
private List feedExecution;
}

Feed Runner Entity

@Entity(name = "FEED_RUN")
@Where(clause = "STATUS_ID <> 4")
public class FeedExecution {

@Id
@Column(name = "FEED_RUN_ID")
private int id;

@Column(name = "BUSINESS_DATE")
@Temporal(TemporalType.DATE)
private Date businessDate;

@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "STATUS_ID")
private Status status;

@Formula("decode((SELECT COUNT(*) FROM file_load fl WHERE feed_run_id = fl.feed_run_id)+(SELECT COUNT(*) FROM event_log ev WHERE feed_run_id = ev.feed_run_id)+(SELECT COUNT(*) FROM error_log er WHERE feed_run_id = er.feed_run_id), 0, 0, 1)")
private boolean executed;

}


Migration from JBoss 4.0 to Tomcat 6.0(JNDI context)

JNDI resources types:
1.Global - myDS
2.Local java:/comp/env/myDS

By default JBOSS has global JNDI context
Tomcat has local JNDI context

To export property:

JAVA_OPTS="$JAVA_OPTS -DpropertyDS=java:/comp/env/myDS"

Where propertyDS - name of system property that will be used in your application

Creating your own maven plugin

Maven plugin:
Project->New->Maven Project->Next then select:


Your Mojo class will look like:

import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;

/**
* Goal which touches a timestamp file.
*
* @goal ddw
*
* @phase process-sources
*/
public class MyMojo extends AbstractMojo {
 /**
  * Location of the file.
  * expression says which parameter to use
  * @parameter expression="${outputDirectory}"

  * @required
  */
 private File outputDirectory;

 public void execute() throws MojoExecutionException {
     File f = outputDirectory;

     if (!f.exists()) {
         f.mkdirs();
     }

     File touch = new File(f, "touch.txt");

     FileWriter w = null;
     try {
         w = new FileWriter(touch);

         w.write("touch.txt");
     } catch (IOException e) {
         throw new MojoExecutionException("Error creating file " + touch, e);
     } finally {
         if (w != null) {
             try {
                 w.close();
             } catch (IOException e) {
                 // ignore
             }
         }
     }
 }
}

This plugin just creates file. Pay attention that comments are really a part of function.
Then you can run it via command line:
mvn groupId:artifactId:version:goal

In this case go to your project directory

mvn com.ddw.plugin:ddw-plugin:0.0.1-SNAPSHOT:ddw -DoutputDirectory="C:\tmp"